Bit-adjuster for rotary cutter-heads.



E. G. WATKINS.

BIT ADJUSTER FOR ROTARY CUTTER HEADS.

APPLICATION FILED FEB.7,1911.

1,032,636. Patented July 16, 1912 0 INVENTOR 44/001 4) (J AttorneyEDWARD G. WATKINS, OF GARDNER, MASSACHUSETTS, ASSIGNOR T SAMUEL J'-SHIMER & SONS, OF MILTON, MASSACHUSETTS.

BIT-ADJUSTER FOR ROTARY CUTTER-HEADS.

Specification of Letters Patent.

Application filed February 7, 1911.

Patented July 16, 1912. Serial No. 607,190.

' State of Massachusetts, have invented a certain new and usefulImprovementin Bit- Adjusters for Rotary Cutter-Heads, and do herebydeclare that the following is a full, clear, and exact descriptionthereof.

In the rotary cutter head which is the subject of the Shimer Patent No.874,871, December 24, 1907, the bit or blade adjusting means consists ofa simple screw located at the back or inner side of the bit holder whichis accessible only by the removal of the bit holder from the cutterhead. i

The object of my invention is to provide a bit adjusting device forcutter heads of the type referred to, which will be convenientlyaccessible at all times without the removal of the bit holder from thecutter head and which will possess otheradvantages, and to this end myinvention consists in the device constructed substantially ashereinafter specified and claimed.

In the accompanying drawingsFigure 1 is a perspective view of a rotarycutter head embodying my invention; Fig. 2 a section thereof on a planetransverse to the axis of revolution, but of onlyafragment of the head;Fig. 3 a section on the line 3-3 of Fig. 2; and Fig. 4 a detail view inperspective of one of the bit holders removed from the cutter head.

The type of cutter head to which my invention relates comprises acylindrical body 10 having an axial hole or opening for the shaft ormandrel, and having in its periphcry a series of longitudinallyextending channels or recesses 11, in each of which is placed one ormore hit holders 12, in the form of a metal block that is provided witha bit receiving slot 13 extending from one edge inward nearly to theopposite edge so as to constitute a clamp for the bit 14 under theaction of one or more bolts 15 whose threaded shank enters a threadedopening 16 in the bit holder while its head is adapted to engage theadjacent side wall of the cut-' ter head recess when the bolt is turnedin the direction as for unscrew ng, and thereby exerts a thrust upon thebit holder whlch produces a pinching or clamping efi'ect ofv the twoportions of the bit holder separated by the slots 13 upon the bit, aswell as, at the same time securely holds the bit holder in its recess inthe cutter head. In the embodiment of my invention that I have selectedfor illustration, there are two bolt holes 16, one near each end of thebit holder and in a thickened portion of the bit holder through whichsaid screw holes pass, and situated between said screw holes in saidthickened portion 17 is an opening 18 which forms a bearing for theouter end of a screw 19, the inner end of which has a bearing in a hole20 in the cutter head body, the threaded portion 21 of the screw beingof somtawhat greater diameter than the inner end that has its bearing inthe hole 20 and extending between said inner end and the inner side ofthe thickened portion of the bit holder. Contiguous to the outer end ofits threaded portion 21, the screw has a collar or annular enlargement22 that forms a thrust bearing to prevent endwise movement of the screwoutward while endwise movement of the screw inward is prevented by theshoulder that is formed at the inner end of the screw by the reducedbearing end thereof in the opening 20. Thus, though the screw 19 is freeto revolve, it is prevented from endwise movement in either direction.Mounted upon the threaded shank 21 of the screwis a nut 23 having aradial projection or finger 24 that projects through a slot 25- nierelywide enough to accommodate it in the bit holder and bears against theinner edge of the blade 14. The nut 23 being prevented from rotating bythe engagement of its lug 24 with the sides of the slot 25, it iscompelled by the rotation of the screw to traverse along the screw, and,of course, by the contact of the lug 24 with the inner edge or heel ofthe blade 14, the blade 14 will be moved outward when the direction ofrotation of the screw is such as to cause an outward movement of thenut. It will thus be seen that I have provided a simple and mostefiicient blade adjusting device which will positively hold the blade inits adjusted position, and as the outer end of the screw 19 is exposedso that it is at all timesaccessible, such adjustment of the blade as.is necessary may most conveniently and quickly be effected.

Instead of the tongue or rib 7 on the inner side of the bit holder whichis employed in Patent No. 874,871 to prevent the bit holder dropping outof the body -or cylinder 10 when the clamping bolts are loose, I providein the rear wall of the holder a threaded hole 26 into which is screwedthe inner end of a screw 27 passing through a hole 28 extending inwardfrom the periphery of the cylinder or body 10. This arrangement ispreferable to the rib and groove device of Patent No. 874,871, becauseit does not require as does the rib and groove arrange ment that the bitholder shall be slid endwise through the recess in the cylinder or bodyin applying it to or removing it therefrom, for which operation it isnecessary to take the cutter head out of the planer. With the screwdevice, evidently, the operation of applying and removing the bit holderto the head can,- therefore, be much more conveniently and easilyperformed. The cylinder or body 10, shown in the drawings, is providedwith the rib -receiving grooves so that such head, if desired, can'beused with bit holders having ribs, as in the patent above mentioned.

Having thus described my invention what I claim is- 1. The combinationof a cutter head having a peripheral recess, a bit holder in said recesshaving an outwardly opening bit-receiving slot, a screw having a bearingin a thickened wall of said bit holder with its operating end outwardlyexposed, and a nut on the screw engaging the inner end of the bit,confined to travel along the screw by the walls of a slot extendinginwardly from the thickened portion of the bit holder.

2. The combination of a cutter head having a peripheral recess, a bitholder in the form of a block having a bit-receiving slot that extendsoutward, a screw having a bearing in said block at one side of said slotand a bearing in the cutter head, and a nut 1,osa,ese

on the screw having a bit-engaging lug, the lug projecting through a'slot in the contiguous wall of the block and engaging the sides thereofto prevent turning of the nut.

3. The combination of a cutter head having a peripheral recess, a bitholder in said recess in the form of a block having a bitreceiving slotthat extends outward, the block, toward its outer end, having its wallcontiguous tothe bit-receiving slot thickened, a screw having a bearingin said thickened wall with its operating. end outwardly exposed, a nuton the screw engaging the in nerend of the bit, said nut playing backand forth in a slot in the block extending inwardly from the thickenedportion of the block wall, and a bolt passing through a threaded openingon the thickened wall at each side of said adjusting screw engagin thebit at oneend, and the contiguous wal. of the cutter head recess at theother end.

4. The combination of a cutter head having a bit holder receiving recessextending from the periphery of the cutter head inward, a bit holderhaving bit-engaging members on opposite sides of the bit, a bolt'engaging an opening in one of said bit-engaging members, and adaptedv tobear against the contiguous wall of said recess, and a bit holderengaging part situated in an opening extending inward from the peripheryof the headand entering a hole inthe bit holder.

In testimony that I claim-the foregoing I have hereunto set my hand.

THATCHER B. DUNN, FLORENCE L. MOORE.

